Off-season spawning of white bass (Morone chrysops) provides producers with the potential advantage of year-round availability of fingerling fish, especially when used in conjunction with cold banking. Additionally, off-season spawning permits producers with the flexibility to optimize the utilization of infrastructure investments moving toward a more continuous batch production cycle instead of the single season cycle currently used in the industry. A seasonal model involves grouping total annual production from a relatively small production window into batches of fish that are pushed for growth and others that are restricted for growth to meet market demands with neither option being optimal.
To better utilize fish rearing and live-feed facilities at Harry K. Dupree Stuttgart National Aquaculture Research Center (SNARC), white bass were conditioned for a year prior to October of 2018. Family crosses are part of the selective improvement of white bass to improve the resulting hybrid. Crosses from domestic and wild sourced white bass were made and reared in about 100 individual 35L tanks. They were fed rotifers (Brachionus plicatilis) and artemia (Artemia franciscana) until transitioning onto a prepared starter (#0) diet about 45 days post hatch. After all the crosses were conditioned to prepared diets the fish were transferred to 250L rearing tanks to quantitate growth and feed utilization on an individual cross basis on a fishmeal free selection diet for the 209 day selection time period.
From each of the family crosses, fish weight, fish length, K-condition factor, and other parameters were measured. White bass performance after the evaluation period was measured in common garden tanks of the 71 crosses and two control groups fed a commercial broodstock diet. Trends of that growth were compared to the growth of the crosses during the evaluation time period. Performance differences between the selection period growth and the post-selection period growth will be contrasted to examine if selection period trends continue based upon parental origin. Additionally, conditioning parameters for off-season spawning of white bass will be presented and discussed.